1. Field of the Invention
The present invention generally relates to semiconductor substrate machining tools and methods, and more particularly to a detailing tool for such applications that is used prior to firing green substrate that is used in semiconductor products.
2. Description of the Related Art
There has been a long felt need to provide a high-volume, low-cost, high-speed method for preparing unfired substrates of the type which are used in electronic applications, for example, to produce multi-layer ceramic (MLC) structures typically used to make single chip modules (SCM) or multi-chip modules (MCM). These substrates may be made from ceramic or composite ceramic/polymer materials. Such substrates are generally planar and square or rectangular in top plan view, with a thickness substantially less than the length and width dimensions. The edges are initially produced with approximately vertical, square edges as seen in side elevational view, which is the design being processed by the invention.
Conventional processes for producing MLC substrate include the steps of casting a ceramic slip to form a green, dried ceramic film of 0.001xe2x80x3 to 0.002xe2x80x3 thickness. These carrier substrate are formed of a ceramic base which is fabricated from a green ceramic of a suitable type such as alumina or beryllia suitably milled in small amounts of suitable lubricants and temporary binders as are well known in the ceramic arts. Initially, printing of a registered matrix of metal pigmented inks to form the electrodes and related structures are performed to form the finished MLC on the ceramic film. Next, lamination of the stack of printed ceramic sheets is performed with pressure and heat to form a compacted structure. Finally, cutting of the compacted structure by a cutter device is performed to form xe2x80x9cchickletsxe2x80x9d that form the substrate.
Conventional processing of these green ceramic substrate prior to firing requires removal of burrs (i.e., tails) from substrate corners. This processing step is crucial since any extraneous burrs remaining on the substrate cause damage to the MLC when fired. Such measures are now done by hand and require careful scrutiny of what is being done. Then, thermal processing, consisting of a drying and bake out cycle, is performed to eliminate the organic components from the green parts, followed by a firing cycle to 2,000 to 2,300 degrees Fahrenheit to form the final ceramic substrate.
It would be desirable to have a tool that is able to clean and remove the tails from green substrate corners effectively and efficiently. Further, soft ceramic/polymer composites as used for IC substrates, are vulnerable to edge delamination in multilayer ceramic packages, by embedded ceramic debris, self-contamination, surface metallurgy damage, and scratching. Therefore, it is desirable not only to protect the substrate from damage during this processing of tail removal, but also to clean any tails while performing this process, thereby obviating substrate contamination.
The present invention solves such problems resulting in an efficient method using a detailing tool as described in the following description and accompanying drawings.
The invention provides a mechanized method and a detailing tool for removal of tails from corners of a green substrate prior to firing. The detailing tool aligns xe2x80x9ctoxe2x80x9d the green substrate prior to removal of the tails within an aligning member. The invention can preferably be used in combination with a rotary table that provides proper indexing of the substrate. Initially, the multiple substrates are placed into a processing holder member of the detailing tool on a rotary table. The substrate is placed on this holder typically by a vacuum attaching force through a void on the underside of the table. The detailing tool initially aligns itself to the substrate on the holder with an air bearing that uses an edge of the substrate as a reference plane. The cutter head assemblies (although one cutter head assembly can be used) that are attached to a slide table member of the detailing tool are then closed (Y-direction). Next, each of the cutter head assemblies close inward in opposite directions (X-direction) at the corners so as remove the tails from the substrate. During this process, any tail debris is siphoned off by a vacuum cleaning action so that no contamination occurs. Next, the cutter head assemblies open and the slide table member moves back to the initial pre-load configuration. Thereafter, the rotary table is indexed by 90 degrees to repeat this process on the other side of the substrate.
Processed substrates are automatically deposited into an output tray every several seconds with the tails from the corners removed and are preferably drawn off by vacuum equipment to free areas of tail debris. The detailing tool is fully automatic and can operate in a multiple station tool to process multiple substrates simultaneously at complimentary stations that cooperatively and progressive index substrates for efficient and cost-effective removal of tails on semiconductor products.
Therefore, one object of the invention is to provide a detailing tool for processing electronic component substrates that include a supporting frame, a substrate carrier movable on the supporting frame to receive and secure the substrate during processing by the tool, and a pair of cutter assemblies attached to the supporting frame for removing tailings on the substrate. Each cutter assembly includes a pair of spaced, translatable and opposed cutters that simultaneously move toward each other while removing the tails from the corners of the substrate (that remains stationary). The pair of cutter assemblies is symmetrically attached to the supporting frame with respect to an axis for indexing the substrate. Thus, the invention can cut opposite edges of the substrate automatically and simultaneously during processing.